An antimicrobial peptide,(1) Magainin I (Mag), was grafted to a titanium oxide surface, via an antiadhesive poly(ethylene glycol),(1349) cross linker The latter plays a 2-fold part, being.. antiadhesive, and enabling the covalent, immobilization of the peptide The functionalization was characterized at each step. by reflection absorption infrared spectroscopy (RAMS) and X-ray photoelectron spectroscopy (XPS). The antiadhesive properties Of PEG, and antibacterial activity of the anchored, Magainin I, were individually tested, toward adsorption of bovin serum. albumin (BSA) proteins, and against Grain positive bacteria, Listeria ivanovii, respectively. The results reveal that adhesion. of both proteins and bacteria have been considerably reduced; accompanied by an inhibition of the growth of remaining adhered bacteria. This work thus offers a novel approach to functionalize oxide surfaces against biofilms and to measure the so obtained properties in each of the successive steps of a biofilm formation.